Project description:MN1 leukemia is a poor prognosis leukemia occuring as MN1 overexpression or fusion with TEL (MN1-TEL), MN1 and MN1-TEL show different biology in terms of dependence of known self-renewal associated genes in leukemia, c-kit positive murine primary bone marrow cells were retrovirally transduced with MN1, MN1-TEL or MN1-TEL mutant MN1-TELdelDBD showing biological similarity with MN1, after retroviral transformation of cells and 10 d culture RNA was extracted and gene expression profiling was assessed
Project description:Myeloid differentiation is blocked in acute myeloid leukemia (AML), but the molecular mechanisms are not well characterized. MN1 is overexpressed in some AML patients and confers resistance to all-trans retinoic acid (ATRA)-induced differentiation. To understand the role of MN1 as a transcriptional regulator in myeloid differentiation, we fused transcriptional activation (VP16) or repression (M33) domains with MN1 and characterized these cells in vivo. Transcriptional activation of MN1 target genes induced myeloproliferative disease with long latency and differentiation potential to mature neutrophils. A large proportion of differentially expressed genes between leukemic MN1 and differentiation-permissive MN1VP16 cells belonged to the immune response pathway like Irf8 and Ccl9. As MN1 is a co-factor of MEIS1 and RARA, we compared chromatin occupancy between MN1, MEIS1 and RARA. Immune response genes that were upregulated in MN1VP16 cells were co-targeted by MN1 and MEIS1, but not RARA, suggesting that myeloid differentiation is blocked through transcriptional repression of shared target genes of MN1 and MEIS1. Constitutive expression of Irf8 or its target gene Ccl9 identified these genes as potent inhibitors of MN1-induced leukemia. Our data show that MN1 prevents activation of the immune response pathway, and suggest that restoration of Irf8 signalling as a novel therapeutic target in AML.
Project description:Myeloid differentiation is blocked in acute myeloid leukemia (AML), but the molecular mechanisms are not well characterized. MN1 is overexpressed in some AML patients and confers resistance to all-trans retinoic acid (ATRA)-induced differentiation. To understand the role of MN1 as a transcriptional regulator in myeloid differentiation, we fused transcriptional activation (VP16) or repression (M33) domains with MN1 and characterized these cells in vivo. Transcriptional activation of MN1 target genes induced myeloproliferative disease with long latency and differentiation potential to mature neutrophils. A large proportion of differentially expressed genes between leukemic MN1 and differentiation-permissive MN1VP16 cells belonged to the immune response pathway like Irf8 and Ccl9. As MN1 is a co-factor of MEIS1 and RARA, we compared chromatin occupancy between MN1, MEIS1 and RARA. Immune response genes that were upregulated in MN1VP16 cells were co-targeted by MN1 and MEIS1, but not RARA, suggesting that myeloid differentiation is blocked through transcriptional repression of shared target genes of MN1 and MEIS1. Constitutive expression of Irf8 or its target gene Ccl9 identified these genes as potent inhibitors of MN1-induced leukemia. Our data show that MN1 prevents activation of the immune response pathway, and suggest that restoration of Irf8 signalling as a novel therapeutic target in AML. C57BL/6J bone marrow cells were harvested from mice treated for 4 days with 150 mg 5-fluorouracil/kg and stimulated for 48 hours in DMEM supplemented with 15% FBS, 10 ng/mL hIL6, 6ng/mL mIL3, and 20ng/mL mSCF. The cells were infected with MN1 or MN1VP16 retroviral constructs by cocultivation with irradiated E86 viral producer cells in the presence of 5μg/mL protamine sulfate (Sigma) for 48 hours and then transplanted into lethally irradiated syngeneic recipient mice. 4 weeks after transplantation MN1, MN1VP16 GFP+ cells and Gr1+/CD11b+ bone marrow cells were FACS-sorted and analyzed by Affymetrix GeneChip Mouse 430 2.0 (43.000 probes) microarrays
Project description:Extensive molecular profiling of leukemias and preleukemic diseases has revealed that distinct clinical entities, like acute myeloid (AML) and T-lymphoblastic leukemia, share the same pathogenetic mutations. It is not well understood how the cell of origin, accompanying mutations, extracellular signals or structural differences in a mutated gene determine the phenotypic identity of the malignant disease. We studied the relationship of different protein domains of the MN1 oncogene and their effect on the leukemic phenotype, building on the ability of MN1 to induce leukemia without accompanying mutations. We found that the most C-terminal domain of MN1 was required to block myeloid differentiation at an early stage, and deletion of an extended C-terminal domain resulted in loss of myeloid identity and cell differentiation along the T-cell lineage in vivo. Megakaryocytic/erythroid lineage differentiation was blocked by the most N-terminal domain. In addition, the N-terminus was required for proliferation and leukemogenesis in vitro and in vivo through upregulation of HoxA9, HoxA10 and Meis2. Our results provide evidence that a single oncogene can modulate cellular identity of leukemic cells based on its active domains. It is therefore likely that different mutations in the same oncogene may impact cell fate decisions and phenotypic appearance of malignant diseases.
Project description:Expression profiling of U937 derived cell lines with induced expression of MN1or MN1-TEL in combination with all-trans retinoic acid (ATRA) Keywords: expression profiling Two similar experiments (A and B, biological duplicates) were performed. Hybridization includes dye swaps. See experimental_design.jpg (below) for detailed setup of the study. In short, different time points after induction of MN1 or MN1-TEL were compared to uninduced samples. The effects of all-trans retinoic acid (ATRA) were also investigated
Project description:Extensive molecular profiling of leukemias and preleukemic diseases has revealed that distinct clinical entities, like acute myeloid (AML) and T-lymphoblastic leukemia, share the same pathogenetic mutations. It is not well understood how the cell of origin, accompanying mutations, extracellular signals or structural differences in a mutated gene determine the phenotypic identity of the malignant disease. We studied the relationship of different protein domains of the MN1 oncogene and their effect on the leukemic phenotype, building on the ability of MN1 to induce leukemia without accompanying mutations. We found that the most C-terminal domain of MN1 was required to block myeloid differentiation at an early stage, and deletion of an extended C-terminal domain resulted in loss of myeloid identity and cell differentiation along the T-cell lineage in vivo. Megakaryocytic/erythroid lineage differentiation was blocked by the most N-terminal domain. In addition, the N-terminus was required for proliferation and leukemogenesis in vitro and in vivo through upregulation of HoxA9, HoxA10 and Meis2. Our results provide evidence that a single oncogene can modulate cellular identity of leukemic cells based on its active domains. It is therefore likely that different mutations in the same oncogene may impact cell fate decisions and phenotypic appearance of malignant diseases. C57BL/6J bone marrow cells were harvested from mice treated for 4 days with 150 mg 5-fluorouracil/kg and stimulated for 48 hours in DMEM supplemented with 15% FBS, 10 ng/mL hIL6, 6ng/mL mIL3, and 20ng/mL mSCF. The cells were infected with MN1, MN1Δ1, and MN1Δ7 retroviral constructs by cocultivation with irradiated E86 viral producer cells in the presence of 5μg/mL protamine sulfate (Sigma) for 48 hours and then transplanted into lethally irradiated syngeneic recipient mice. 4 weeks after transplantation, MN1, MN1Δ1, and MN1Δ7 leukemia cells and Gr1+/CD11b+ bone marrow cells were FACS-sorted and analyzed by Affymetrix GeneChip Mouse 430 2.0 (43,000 probes) microarray.
Project description:To study the function of anti-MN1 sdAb in MN1-positive tumour cells, we treated U2OS cells with anti-MN1 sdAb and performed RNA-seq.
Project description:Our results revealed that among all 273 metabolites detected, the levels of metabolites involved in glucose-related glycolysis and gluconeogenesis were elevated in GCN2 deleted HSPCs. Moreover, GCN2 deletion specifically increased mitochondrial OXPHOS and suppressed anaerobic glycolysis in HSPCs.
Project description:Purpose: To characterize transcriptional changes associated with homozygous inactivation of Men1 in MN1 driven AML Methods: In vivo MN1 transformed cells were transduced with Cre-vector to inactivate Men1 and injected into sublethially irradiated syngeneic recipients. Men1-/- and Men1wt MN1-driven leukemic cells were isolated from moribund recipients and plated in methylcellulose for 7 days before RNA was extracted. Results: Men1-/- MN1-driven leukemic cells failed to propagate leukemia in most secondary recipients, in comparison with Men1wt MN1-driven. In vitro, cells had lost their colony forming activity. Gene expression analysis revealed a downregulation of the MN1 leukemic expression program. Conclusions: Men1 regulates long term maintenance of MN1-driven leukemia.